High frequency pulse width modulation driver, particularly useful for electrostatically actuated MEMS array
US6543286B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 19, 2001 |
| Grant date | Apr 8, 2003 |
| Priority date | — |
| Expiry date | Jun 19, 2021 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04Q2011/0049
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Pulse-width modulation (PWM) drive circuitry particularly applicable to an array of electrostatic actuators formed in a micro electromechanical system (MEMS), such as used for optical switching. A control cell associated with each actuator includes a register selectively stored with a desired pulse width. A clocked counter distributes its outputs to all control cells. When the counter matches the register, a polarity signal corresponding to a drive clock is latched and controls the voltage applied to the electrostatic cell. In a bipolar drive, one actuator electrode is driven by a drive clock; the other, by the latch. The MEMS element may be a tiltable plate supported in its middle by a torsion beam. Complementary binary signals may drive two capacitors formed across the axis of the beam. The register and comparison logic for each cell may be formed by a content addressable memory.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.